In the past, various means have been used to cage a gyro gimbal. U.S. Pat. No. 4,193,308 suggests the use of automatic brakes, solenoids or dampers to cage a gyro gimbal. These devices are placed in physical contact with the gyro gimbal.
U.S. Pat. No. 4,322,984 shows a mechanical locking means that cages a rotor of a gyro. The locking means is not dynamic. That is, the locking means does not immediately respond to sidewise movement of the rotor. Further, the locking means is placed in physical contact with the rotor.